I am a Kansas City Photographer and can be found at http://kimberlypimentel.com/
The Canon 70-200 2.8 L series with IS- and it does not disappoint. I have used this lens before as I have suggested always Rent first I did at Borrowlenses.com. I rented a 70-200mm f4 with no stabilization and was not impressed the images lacked the crispness that I wanted.
The canon 70-200 2.8 with IS had what I needed. For me having smaller hands this is a big lens and heavy after a day of shooting you will feel this lens. The IS is needed to provide that extra edge for your images. This beauty of a lens provides incredible prime like images at 70mm and 200 mm. The quality is apparent with superb depth and accurate saturations not to mention a spot on focus that can best be described as tack sharp. I would have to say that this lens is the BMW of camera lenses- Quality, Speed, Agility, Craftsmanship-you get what you pay for as the saying goes- and with this canon L Series piece I will be getting a lifetime of quality Portraiture.
Lens purchases for a Photographer are definitely costly when one starts to consider the L Series of Canon glass. I would suggest renting glass before buying so that hasty purchases are not made. My first L series lens purchase was the 50mm 1.2, the second was my 70-200 mm 2.8 with IS stabilization.